Naltrexone Naltrexone is a pure opiate antagonist and, as such, is
not considered a substitution medication for an agonist. However, it has recently
received considerable attention when used for "ultra-rapid" detoxification
under general anaesthesia. In addition to its use as a rapid detoxification
agent, naltrexone has also been utilised for decades as a longer-term "blocking
agent" in maintenance treatment.

A Cochrane review on the effectiveness of naltrexone maintenance
treatment did not find evidence for its effectiveness in maintenance therapy,
however. A trend in favour of treatment with naltrexone was observed for certain
target groups (particularly people who are highly motivated), as has been previously
described in the literature (Kirchmayer, 2003).